<Project>

  <Target Name="TestGeneratingReferencePathItems" BeforeTargets="BeforeBuild;BeforeResolveReferences;ResolveAssemblyReferences">
    <ItemGroup>
      <_ExtraReferenceItem Include="$(MonoPath)\System.ComponentModel.Composition.dll">
        <CopyLocal>false</CopyLocal>
        <Test>test-value</Test>
      </_ExtraReferenceItem>
    </ItemGroup>

   <RemoveDuplicates
      Inputs="@(_ExtraReferenceItem)">
      <Output
        TaskParameter="Filtered"
        ItemName="ReferencePath" />
    </RemoveDuplicates>
  </Target>
</Project>